1. Technical Field
The present invention relates to a piezoelectric ignition mechanism for gas lighters, range tops, outdoor gas grills, or the likes, which comprises a device capable of selectively inhibiting the production of sparks by the piezoelectric ignition mechanism to resist undesired use of the lighter by young children.
2. Background Art
Recently, attention has been directed toward preventing ready actuation of cigarette lighters by persons normally not able to appreciate the potential danger of the flame. Such danger includes the potential to burn the individual directly or to burn surrounding areas or items. The individuals contemplated in these efforts are young children in the age category of under five years of age.
As known, piezoelectric mechanisms generally consist of a telescopic assembly comprising an upper member and a lower member, which are capable of moving relative to each other. The outer and inner members are normally kept at a predetermined distance from each other by a return spring. A crystal or piezoelectric element is normally embodied in the upper member of the telescopic assembly. An electrical spark is produced when a hammer or "plexor" impacts the piezoelectric element. The piezoelectric element, in turn, is placed between an "anvil" member, and the "impact pad", which actually receives the impact from the plexor.
The plexor is slideably disposed in the axial void of the telescopic assembly. In the rest position, the plexor is disposed at a predetermined distance away from the impact pad by means of a retaining mechanism. An impact spring is normally positioned between the plexor and the lower telescopic member to bias the plexor toward the impact pad.
To produce a spark, a manual compressive force is applied to the telescopic assembly causing the upper and lower members to move toward each other. This action also compresses the return spring which separates the upper and lower members, and simultaneously compresses the impact spring to store energy therein. Near the end of the contraction of the telescopic assembly, the plexor is released from the retaining mechanism and the compressed impact spring drives the plexor toward the impact pad, creating the impact energy to generate the electrical potential across the piezoelectric element. Said potential is conducted through other conductive elements in the cigarette lighter, which make up an electrical circuit. This circuit has an open gap located near the valve where the fuel from a fuel supply is released. Said potential creates a spark across the gap and ignites the released fuel to create a flame. An example of such piezoelectric mechanism is disclosed in U.S. Pat. No. 5,262,697 entitled "Piezoelectric Mechanism For Gas Lighters". The disclosure of the '697 is hereby incorporated by reference.
It is desirable to increase the difficulty of using lighters to limit the ability of young children under five years of age to operate such piezoelectric lighters. For this reason, there are attempts to provide "child-resistant" piezoelectric lighters offered in the patent literature. Examples of such patents include U.S. Pat. Nos. 5,145,358, 5,240,408, 4,904,180, 4,859,172, 4,786,248 and 5,228,849. Each of these disclosed devices has in common the fact that depression of the thumb pad, which compresses the telescopic assembly and activates the piezoelectric mechanism, is prevented by a latch member to inhibit the production of sparks. Normally, the latch member is disposed between the thumb pad and a wall of the lighter body. This latch member must be aligned or positioned precisely between the thumb pad and the wall of the lighter body in order to prevent the depression of the thumb pad.
Thus, there remains a need for a device, which increases the difficulty of operating a piezoelectric ignition mechanism and which would not require the precise alignment of the latch member in order to inhibit the production of spark.